Apparatus for treating metal articles



v Dec. 15, 1942. D. c. TURNBULL APPARATUS FOR TREATING METAL ARTICLESFiled May 17, 1940 9 Sheets-Sheet l we 2 22 a I w s G N N z: 5% m: m u wINVENTOR & flaw?! Ernhz/l N BY ATTORNEY A Dec. 15 1942. D. c. TURNBULL2,305,451

APPARATUS FOR TREATING METAL ARTICLES Filed May 17, 1940 9 shee s-sheet2 ATTORNEY Dec. 15, 1942. 1:). c. TURNBULL 2,305,451

APPARATUS FOR TREATING METAL ARTICLES Filed May 17, 1940 9 Sheets-Sheet3 g INVENTOR '39 I 1 75010 ["YlavMa/l mw l ATTO RN EY 1 19421. D. c.TURNBULL ,451

APPARATUS FOR TREATING METAL ARTICLES Filed May 17, 1940 9 Sheets-Sheet4 241 'fl /v' INVENTOR ATTORNEY 7 Dec. 15, 1942. D. c. TURNBULLAPPARATUS FOR TREATING METAL ARTICLES Filed May 17, 1940 V 9Sheets-Sheet 6 INVENTOR v fill/1d I. YZ InZa/Z ATTORNQE'F xKNN 1366-1942- D. c. TURNBULL APPARATUS FOR TREATING METAL ARTICLES Filed May 17,1940 9 Sheets-Sheet 7 ATTORNEY Dec. 15, 1942. D c. TURNBULL. 2,305,451

APPARATUS FOR TREATING METAL ARTICLES Filed May 17, 1940 9 Sheets-Sheet8 INVENTOR TORNEY Dec. 15, 1942.

D. c. TURN BULL 2,305,451 APPARATUS FOR TREATING METAL ARTICLES FiledMay 17, 1940 9 Sheets-Sheet 9 A \wnw. I V l 1 www m .4! .i. x "n a .mllwm mwu afl M L 4 H m a W IM N f .R 1 5 W vfiN'i o m .IIIL .MA M i 1!. We4 1 M mum Nun kw I Patented Dec. 15, 1942 APPARATUS FOR TREATING METALARTICLES David C. Turnbull, Mishawaka, I nd., assignor to The AmericanFoundry Equipment Company, Mishawaka, Ind., a corporation of DelawareApplication May 17, 1940, Serial No. 335,662

17 Claims.

This invention relates to apparatus for treating metal articles. andmore particularly to abrading apparatus for cleaning, polishing, orotherwise treating the surfaces of castings, forgings, stampings, andsimilar metal workpieces. This application is a continuation-in-part ofmy copending application Serial No. 231,499, filed September 24, 1938,now Patent No. 2,204,636, dated June 18, 1940.

The apparatus forming the subject matter of this invention is of thetype generally referred to as a tumbling mill, and is so designed thatthe workpieces to be cleaned or treated may progress continuouslythrough the mill without in terruption and during their movement aresubjected to blasts of abrasive which removes en crusted molding sand,scale, irregular projections and foreign matter with which the surfacesof the workpieces are coated. The abrasive projectors preferablycomprise one or more abrasive throwing wheels each of which projects afanshaped stream of abrasive particles against the workpieces supportedon a moving tumbling member. The tumbling member preferably comprises acontinuous belt comprising a series of longitudinally extending slatssupported by and connected to the links of spaced chains. The workpiecetumbling belt is supported upon a pair of spaced shafts provided withsprockets part of the belt. The belt is suspended in such a manner thatthe upper flight thereof provides a workpiece receiving cavitypositioned between the spaced belt supporting shafts.

In accordance with this invention, the slats :2.

and supporting links which form the tumbling belt are so shaped that theslats overlap one another to provide a shingled surface during theirtravel through the upper concave run of the belt. This improved featureserves to protect th belt chains and operating mechanism from the blastprojected into the concave upper run of the belt, removes thepossibility of the workpieces becoming attached to the belt slats, and.further, produces a more uniform and positive tumbling and progressivelyadvancing movement of the workpieces through the fan-shaped stream orstreams. The belt is further so constructed that.

'the slats spread apart during their movement through the outer or lowerrun of the belt so as to release and shed any abrasive or foreignparticles that may be clinging thereto.

As a further feature, one of the belt supporting shafts is positioned atan elevation above the other shaft, so that the inner run of the belttraveling upwardly toward the higher shaft will more effectively andpositively throw off and tumble irregular shaped workpieces thatotherwise might have a tendency to cling to the belt or, otherwisedepart from their proper course.

The tumbling belt is supplied with workpieces from a generally tubularfeed drum which is supported to rotate with the movement of the up' perrun of the tumbling belt. The inner end of the feed drum and theadjacent end of the tumbling belt are operably connected so that theymay be driven as a unit. The inner end of the feed drum also maintainsthe cross-sectional contour of the upper run of the belt in conformitywith the cross-sectional contour of the adjacentend of the feed drum.The inside diameter of the discharge end of the feed drum is whichpositively engage the chains forming a sat slightly smaller than theinside diameter of the adjacent end of the concave upper run of thetumbling belt so as not to obstruct the smooth passage of the workpiecesfrom the drum to the belt.

The workpieces which havemoved through the upper concave run of thetumbling belt drop into a rotatably mounted discharge drum withoutobstruction by making the inside diameter of the adjacent end of thisdrum slightly larger than the inside diameter of the adjacent end of theupper run of the tumbling belt. Projections extending from one endof thetumbling belt engage the discharge .drum to rotate the same. These drumengaging projections also maintain the cross-sectional contour of theworkpiece supporting run of the tumbling belt at the discharge endthereof in conformity with the cross-sectional contour of the adjacentend of the discharg drum. Thus by positively driving only one or, ifdesired, both conveyor belt supporting shafts, the tumbling belt may beoperated to effect tumbling action of the workpieces supported withinthe upper concave run thereof and at the same time rotate both thefeeding drum and the discharge drum.

As the workpieces pass through the feeding drum they also undergotumbling Or agitating action, which shakes loose some of the undesirableforeign matter clinging to the workpieces before they pass onto thetumbling belt. The undesirable foreign particles thus shaken loose aredischarged through perforations in the drum and are conducted into asuitable hopper. The cleaned and treated workpieces passing off thedischarge end of the tumbling belt pass into the discharge drum wherethey" are subjected to further tumbling or agitating action which shakesloose any abrasive or: foreign particles that may cling thereto. Thisabrasive or foreign matter escapes through perforations or openings inthe discharge drum and passes into a suitable hopper therebeloW. I

The feed drum, tumbling belt and discharge drum are contained withinan'enclosed cabinet which contains transverse partitions or bulkheadswhich support parts of the operating mechanism and also serve to dividethe cabinet into a feeding chamber, a blasting chamber and a dischargechamber. The. feed end of the cabinet may be provided with a suitableworkpiece receiving hopper which may be continuously supplied withworkpieces by a suitable conveyor. The feed hopper communicates with theadjacent end of the feed drum. Theentry opening is normally closed toprevent abrasive, foreign particles and dust from escaping by flexiblerubber curtains. The discharg end of the cabinet may be provided with asuitable discharge chute into which the workpieces are discharged fromthe discharge drum. The discharge opningsmay also be closed by flexiblerubber curtains. This chute maybe made to communicate with a suitableconveyor designed to convey the cleaned and treated Workpieces to aselected location in the plant.

The driving motor and associated power transmission mechanism which isoperably connected to the tumbling belt shaft, may for convenience bemounted on the top of the cabinet. The abrasive throwing wheel or wheelsand associated driving motors and power transmission mechanism may alsobe supported upon the top wall of the cabinet. The abrasive throwingwheels are preferably so mounted that their plane of rotation xtendsgenerally parallel to the longitudinal axis of the upper run of theconveyor belt but with the plane of rotation of each wheel inclined tothe vertical so as to project its abrasive stream against the castingssupported on the uptraveling side of the upper run of the conveyor belt.More thorough and uniform cleaning of the workpieces is thus assuredwith the least possible damage to the tumbling belt.

As a further improved feature, the cabinet is pivotally supported on atransverse axis so that the feed drum, tumbling belt and discharge drummay be tilted along their longitudinal axes so as to cause theworkpieces to progressively advance therthrough. A heavy shaft supportedupon suitable sturdy standards and extending transversely cf the cabinetmay provide th pivoting support upon which one end of the cabinet rests.Suitable cabinet tilting mechanism which may comprise a hydraulicallyoperated jack is connected to the other end of the cabinet to effect thedesired longitudinal tilting movement of the cabinet and its associatedtumbling belt, feed drum and discharge drum contained therein. Suitablesupports may be provided for retaining the cabinet in any desired tiltedposition so as to remove the load from the jack during operation.

By means of the tilting mechanism thus provided, the feed drum, tumblingbelt and discharge drum may be positioned at any desired longitudinallyinclined angle which may vary from a substantially horizontal plane orzero inclination to an inclination of 30 from the horizontal, dependingupon the shape characteristics of the workpieces to be treated. It willbe appreciated that workpieces which are relatively. short in lengthwith few projections will be more inclined to advance longitudinallythrough the cabinet when inclined at a lesser angle than relatively longor markedly irregular pieces. Adjustment oi the longitudinal inclinationof the feed drum. tumbling belt and the discharge drum may be effectedto advance the particular workpieces under treatment therethrough at thedesired cleaning speed. The driving mechanism for the tumbling belt isalso constructed so that the tumbling belt may be driven at any desiredspeed best suited for the most effective cleaning and treatment of theselected workpieces. It will be appreciated that certain classes ofworkpieces require less blasting treatment than other classes ofworkpieces and the speed at which the tumbling belt is to be driven toobtain the best results is determined by these factors.

Almost any number of abrasive throwing wheels, of any desired size orabrasive throwing capacity, may be associated with this tumbling mill bycorrespondingly lengthening or shortening the tumbling belt slats and byvarying the size and cross-sectional contour of the upper run of theconveyor belt. Thus this apparatus embodies all the characteristicsdesired for high speed mass production cleaning and treatment ofnumerous different shapes, types and kinds of castings, forgings,stampings, bars and other metal workpieces. The apparatus can beadjusted to rapidly, thoroughly and uniformly clean the numerousdifferent types and shapes of workpieces which must be cleaned andtreated in a large foundry, and thus supplies the flexible high speedunit which the industry has long sought.

An object of this invention is to provide blast cleaning and treatingapparatus whereby numerous different shapes of metal castings, forgings,stampings and metal workpieces can be uniformly and thoroughly cleanedand treated at high production speeds and in a continuous manner withoutrequiring shutdowns for loading orunload- Another object of thisinvention is to provide a sturdy and highly practical continuoustumbling mill of high production capacity which may be adjusted andmanipulated to give the desired cleaning and treating action to numerousdifferent shapes and kinds of workpieces.

Another object of this invention is the provision of blast cleaningapparatus wherein the workpieces are automatically manipulated to re-'move therefrom molding sand and other foreign material prior to entry ofthe workpieces into the abrasive stream.

Anotherobject of this invention is the provision of apparatus whereinthe workpieces to be cleaned and treated are automatically manipulatedafter they emerge from the abrasive stream to remove abrading materialor other debris from the surfaces of the workpieces and from thecavities or depressions-therein.

Another object of this invention is to provide an improved conveyoroperable to tumble the workpieces residing in the abrasive stream, whichis so constructed as to protect operating parts of the conveyor andother mechanism comprising the apparatus from the abrasive blast so asto reduce breakdown and repairs, which produces posi ive tumbling andspiralling advance movement of the workpieces under treatment, and whichis free from projections which might have a tendency to interfere withthe proper tumbling and spiralling movement of the workpiecestherethrough.

Various other features and advantages of the invention will be apparentfrom the following particular description and from an inspection of theaccompanying drawings.

Although the novel features which are believed to be characteristic ofthis invention will be particularly pointed out in the claims appendedhereto, the invention itself. as to its objects and advantages, and themanner in which it may be carried out, may be better understood byreferring to the following description taken in connection with theaccompanying drawings forming a part hereof, in which Fig. 1 is a topplan view of the continuous blast cleaning mill with mechanical conveyorfor supplying the metal workpieces thereto;

Fig. 2 is a side elevational view of the blast cleaning mill;

Fig. 3 is an end elevational view of the mill as it appears at thefeeding end thereof;

Fig. 4 is an end elevational view of the mill as it appears at thedischarge end thereof;

Fig. 5 is a longitudinal cross-sectional view through the mill takenthrough the feeding chamber, the tumbling chamber, and the dischagechamber;

Fig. 6 is a fragmentary transverse cross-sectional view through thecabinet and tumbling belt, showing more particularly the manner in whichthe feed end of the belt engages with and conforms to the egress end ofthe feed drum, this view showing the construction as it appears whenlooking in the direction of the arrows 6-6 of Fig. 5;

Fig. 7 is a fragmentary cross-sectional view taken through the cabinetand feed drum, showing the arrangement of the drum supporting rollersand as the same appear when looking in the direction of the arrows 'IIof Fig.

Fig. 8 is a perspective view of the egress end of the feed drum, showingthe drum in engagement with a projection extending from the end of oneof the tumbling belt slats;

Fig. 9 is a fragmentary cross-sectional view through the cabinet andtumbling belt, which illustrates the tumbling belt and its supports ingreater detail, this view also showing the inclined position of theabrasive throwing wheel which directs the abrasive blast against theworkpieces supported on the uptravel side of the inner concave run ofthe conveyor belt and as the same appears when looking in the directionof the arrows 9--9 of Fig. 5;

Fig. 10 is a fragmentary cross-sectional view through the cabinet anddischarge drum, showing the pin projections extending from the ends of.certain of the belt slat-s in engagement with the drum to rotate thesame, and with the rollers on the ends of the slats supported by theguide track carried by the adjacent bulkhead wall, as

these parts appear when looking in the direction of the arrows Ill-40 ofFig. 5;

Fig. 11 is a transverse cross-sectional view through the cabinet anddischarge drum, showing particularly the arrangement of the rollerswhich rotatably supo'rt th drum, as the same appear when looking in thedirection of the arrows II-II of Fig. 5;

Fig. 12 is an enlarged fragmentary perspective view of the tumblingbelt. showing more particularly certain details of the slat supportingchain. drum engaging pins, and thrust rollers;

Fig. 13 is a top plan view of a fragmentary portion of the tumblingbelt. showing further details of the belt supportin'g'chain, drumengaging pins. and thrust rollers: and

Fig. 14 is a side elevational view of a similar Similar referencecharacters refer to similar parts throughout the several views of thedrawings and the specification.

Referring to the drawings, the articles or workpieces w to be cleanedand treated are supplied to the mill in a continuous stream by means ofa suitable conveyor, such as the belt conveyor I, shown moreparticularly in Fig. l. The workpieces from the conveyor are dischargedinto a hopper 2, from which they move by gravity into a feeding chamber3 where they are given an initial tumbling action which effects partialremoval of the loose sand, scale and debris from the surface thereof.The workpieces w move from the feeding chamber into the tumbling chamber4, where the workpieces are impinged by the abrasive blast. Theworkpieces are discharged from the lower end of the tumbling or blastcleaning chamber into a discharge chamber 5 where they undergo furthertumbling action to remove any blast-loosened scale, debris and abrasiveparticles clinging thereto. The workpieces are emptied from thedischarge chamber into a suitable discharge chute 6. which may be of anydesired or convenient form.

The feed chamber, tumbling or blast cleaning chamber and dischargechamber are contained within a suitable enclosed housing 20 supportedupon a suitable pivoting mechanism 1 whereby the housing 20 and themechanism supported therein and thereon may be tilted in a longitudinaldirection to effect the desired advance of the workpieces therethrough.Raising and lowering devices 8 are provided whereby the desired tilt or.inclination can be given to the feed drum. tumabrasive-is withdrawnfrom the abrasive storage bin in a controlled manner and is conducted bysuitable abrasive receivers and feed tubes to.

abrasive projectors, which preferably comprise one or more abrasivethrowing wheels I0.

The feeding chamber 3 contains a tubular feed drum II having open endsinto which the workpieces are fed from the hopper 2. The blastingchamber 4 contains a workpiece supporting conveyor I2 which presents agenerally arcuate interior surface upon which the workpieces aresupported and tumbled during their longitudinal advance therethrough.The conveyor I2 may comprise a continuous belt formed fromlongitudinally extending slats II!) which are connected to a pluralityof spacedlchains I3 each trained over a pair of spaced generallylongitudinally extending shafts I4 and IS. The workpieces dischargefrom" the conveyor I2 into a tubularshapeddischarge drum I6, preferablyof generally" truncated conical form. which is contained within thedischarge chamber 5. The conveyor or' tumbling belt I2 is driven bysuitable driving mechanism I] operably connected to one of the conveyorbelt supporting shafts I4. 7

The tubular feed drum H is rotatably support- 3| in the front wall 23and the workpiece egress end of the conveyor belt l2 and thus rotatedthereby.

Referring more particularly-to Figs. 1, 2. 3, 4 and 5. the cabinet 23which defines the feeding chamber, blasting chamber and dischargechamber. presents enclosing metal plate reinforced and strengthened bystructural framework. The cabinet generally comprises spaced side walls2| and 22, a front end wall 23, and a rear end wall 24. The bottom ofthe cabinet is shaped to provide an abrasive and refuse receiving hoppercomprising a pair of downwardly inclined bottom walls 25 and 26 whichconverge from the front and rear end walls 23 and 24, and a downwardlyinclined side bottom wall 21 which converges from the side wall 22toward the side wall 2|. It will be noted that the bottom hopper formingwalls 25, 26 and 21 converge to provide a discharge outlet 28 for theabrasive, sand and refuse adjacent the side Thus the cabinet presents agenerally boxlike structure having a generally hopper-shaped bot-. tomalong which the abrasive and refuse may slide to a common dischargepoint. The bottom of the cabinet thus provides an abrasive and refusereceiving hopper which may be so shaped as to conduct the abrasive andrefuse by gravity into a funnel shaped receiver at the boot of theelevator tower 3|].

The front end wall in Figs. 3 and 5, is provided with a circular opening3| whose diameter approximates the inside diameter of the tubularworkpiece feeding drum The cabinet is provided with a top wall 32 whichprovides a covered enclosure for the feeding chamber 3. A top wall 35provides a cover for the blasting chamber 4 and a top wall 36 provides acover for the discharge chamber 5. A bulkhead wall 33 which extendsbetween the side walls 2| and 22 provides a partition wall whichseparates the feeding chamber 3 from the blast cleaning chamber 4. Thebulkhead wall 33 also provides a support for the two spaced bearings 5|each of which receives and rotatably supports one end of the conveyor l4and I5. The bulkhead wall 33 is also provided with a circular opening 34through which the egress end of the tubular workpiece feeding drumextends. The lower end of the bulkhead wall 33 is provided with asuitable opening or openings 31 which permit the abrasive and refuse toslide down the inclined bottom wall 23 without obstruction. The top wall32 of the feeding chamber extends between the side walls 2| and 22,the'ffront end wall 23, and the bulkhead wall 33, so that the feedingchamber is completely enclosedexcept for the workpiece entering openingdischarge opening 34 in the bulkhead wall 33.

As shown more particularly in Figs. 5 and 11,

a heavy bulkhead wall 38 extending between the side walls 2| and 22separates the blast cleaning chamber 4 from the discharge chamber 5. Thebulkhead wall 38 also provides a support for the two spaced bearings 52,each of which supports walls formed from heavy 1 wall 2| of the cabinet.

23 of the cabinet, as shown belt supporting shafts converging front andrear A rectangular frame the adjacent end of one of the conveyor beltsup porting shafts l4 and |5., The bulkhead wall 38 is provided with acircular opening 39 through which the smaller end of the tubularworkpiece discharge drum l6 extends. The rear end wall 24 of the cabinetis also provided with a circular opening 40. as shown in Figs. 4 and 5,through which the larger end of the workpiece discharge drum l6 extends.The top wall 36 for the discharge chamber extends between the side walls2| and 22, the rear end wall 24, and the bulkhead 38. The bulkhead walls33 and 38 are formed of heavy metal plate suitably stiffened andreinforced to support the workpieces contained within the conveyor belt|2, the belt supporting shafts I4 and |5, and associated mechanism. Itwill be noted that the top wall 35 which covers the blasting chamberextends between the bulkhead walls 33 and 38 and between the side walls2|" and 22, and that preferably the top wall 35 is inclined slightlyfrom the sidewall 2| toward the side wall 22 for a purpose which willpresently appear.

Access to the feeding chamber 3 may be had througha suitable openingprovided in the side wall 2|, which is closed by a door 4| supportedupon hinges 43. The door may be held in closed position by means of apair of latches 42. Access to the blast cleaning chamber 4 may also behad through a suitable opening provided in the side wall 2|, which isclosed by a door 44 supported by hinges 46 and held in closed positionby means of suitable latches 45. The cabinet 2|! is sturdily constructedand reinforced to withstand shock and vibration and adequately supportthe operating mechanism associated therewith and the workpieces passingtherethrough.

The cabinet as shown in Figs. 2, 3 and 4, is supported upon a pair ofrear legs 41, one of which is secured to the side wall 2| of the cabinetand the other secured to the side wall'22 of the cabinet, and a pair offront legs 48, one of which is secured to the side wall 2| and the othersecured to the side wall 22 of the cabinet. Each of the rear legs 41 isprovided with a bearing 49 adjacent the lower end thereof through whicha cabinet supporting shaft 50 extends. It will be noted that the shaft50 extends through the inclined side bottom wall 21 and the side wall 2|of the cabinet. Each end of the shaft 50 extends through a hearing 53carried by a bracket plate 54. The spaced bracket plates 54 are carriedby a pair of inclined supporting beams 55, the upper ends of which aresupported by a pair of vertical uprights 56 which rest upon the millfloor I. The spaced supporting uprights 56 may be rigidly connected by acrossframe 51 so as to provide a rigid and sturdy construction.

The front supporting legs 48 are connected by a horizontally extendingbeam member 58. The front end of the cabinet is normally supported upona pair of spaced uprights 58 whose upper endsyare connected by ahorizontally extending framing member 60 and by a pair of spacedhorizontal frame members 6| connected to the mid section thereof. Thelower end of the inclined bracing frame members 55 may be suitablysecured to the lower end of the upright members 59. 68 adjacent the millfloor connects the uprights 5G and 59 to provide a sturdy cabinetsupporting framework.

A pair of threaded posts 62, as shown in Figs. 2 and 3; are eachhingedly secured to the horizontally extending frame member 58. Abracket 63 secured to the frame member 58 is provided with a pair ofspaced wing portions between which manner.

posts 62 so that each of the threaded posts 62 is permitted to pivotabout its hinge pin 64. The lower end of eachpf the threaded posts 62extends through a hole in a bracket 66 firmly secured to the adjacentupright 59. A hand wheel 66 provided with a threaded nut portion 61 isthreaded over the threaded shank of each of the posts 62 and is adaptedto rest against the adjacent bracket 65. By proper manipulation of thehand wheel 66, the front end of the cabinet may be rigidly supported atthe desired. elevation so as to give the proper longitudinal inclinationto the cabinet.

Since the cabinet and its associated mechanism is of very substantialweight, it is preferable to 'provide mechanical means to raise and lowerthe front end of the cabinet to give it the desired longitudinalinclination. A hydraulic jack is illustrated for this purpose, which maybe-of any well known construction but sturdily'bullt to lift severaltons in weight. The hydraulic Jack shown for purpose of illustrationcomprises generally a cylinder I provided with a vertically reciprocableThe lower end of the cylinder 10 is piston 1 I. suitably mounted upon asuitable pedestal I2 upon which is supported a pair of spaced bracketsI3- between which a supporting lug I3 fixed to the lower end of thecylinder I0 extends. A pivot pin I4 extends through the spaced bracketsI3 and the supporting lug I3 so as to permit the cylinder 10 to pivotthereabout. The upper end of the piston II extends between a pair ofspaced brackets I6 which are fixedly secured to approximately the midsection of the horizontal frame member 69. The upper end of the pistonII is pivotally connected to the brackets I6 by means of a hinge pin 11.v

The hydraulic jack is driven by a suitable hydraulic pump I6 whichtransmits liquid pressure to the lower end of the cylinder through apressure tubing I9- connected to the lower end of the cylinder I0 andthe pump 19 in a leakproof A pressure control valve 15 located in thefront end wall 23 of the cabinet. The hopper comprises an inclinedbottom wall 85 and tapered side walls 96 suitably secured as by bracingvto the front end wall 23. The lower end of the bottom wall 85 mergesinto an arcuate-shaped feed chute 81 whose inside diameter is slightlyless than the inside diameter of the tubular feed drum II. Theworkpieces roll down the hopper the pressure tube line I9 provides meansfor controlling the flow of pressure supplying liquid, such suitableplatform 84 resting on the spaced horizontal supports 6|. The pressurepump I8 and control valve I5 may be of a type commonly employed withhydraulic jacks to control the operation of the hydraulic jack so thatthe front end of the cabinet may be raised or lowered to any extentdesired. It will be appreciated that when the front end of the cabinethas been raised or lowered the required extent, the hand wheels 66 areturned down to rest against the supporting brackets so that'the threadedposts 62 support the front end of the cabinet in the desired incl nedposition and relieve the jack from further strain. It will be furtherappreciated that the cabinet tilts or rocks about the rock shaft 50 andwith this arrangement the cabinet may be 2 and in to the tubular feedmember II. An. apron 98 extends across the side walls 86 of the hopper,from which a plurality of flexible rubber curtains 99 may be suspendedto normally seal the openings 3| leading into the feeding chamber. Theflexible curtains 89 will readily flex so as to permit the workpieces toroll into the feed drum II but at the same time prevents reboundingabrasive, dust and'debris from escaping from the cabinet through thefeed opening 3i.

The tubular feed drum II, as shown in Figs. 5, 7 and 8, is generallycylindrical in cross-section and is provided with open ends. It ispreferably made of heavy wear resisting metal plate and of sufficientstrength to support several hundred pounds of castings or similarworkpieces which are tumbled therein. A pair of spaced track formingdiscs 90 are fixedly secured to the tubular wall of the drum II toprovide means upon which the drum II is rotatably supported. Each disc90 may be further stiffened and reinforced by spaced webs 9| welded tothe discs 90 and the tubular wall of member II. Each disc 90 is providedwith a rim forming flange 90' upon which a circular track member 92 issupported, the track. 92 being'secured to the flange 90 as by screws.

As shown more particularly in Figs. 5 and 7, I

the feed drum II is supported upon three pairs of equally spaced flangedwheels. One pair of Wheels 95 are rotatably suspended from the top wall32 of the feeding chamber by means of a suitable bracket 99. The pairedwheels 95 are fixed to a shaft 99 rotating in bearings I 00 which arerigidly suspended from the brackets 98. Another pair of wheels 96 arefixed to a shaft I 0! rotatably supported by bearings I02 carried by across beam I03 supported by bracing brackets I04 attached to the sidewalls 2| and 22 of the cabinet by bolts given any "desired longitudinalinclination to cause the workpieces to move through the cabinet at thedesired speed.

The hopper 2 into which the workpieces are discharged from the conveyorI is supported upon I06. Another pair of wheels 91 are similarlysupported upon a shaft IOI rotatably mounted in spaced bearings I02.resting on the cross beam I03. The paired wheels 95, 96 and 91 arearranged to roll upon the circular tracks 92 which are fixed to andcarried by the feed drumv It so that the feed drum willfreely rotateabout its longitudinal axis. The spaced wheels 95, 96 and 91 are eachprovided with spaced flanges I05 to retain the wheel upon the tracks 92which are so shaped as to seat between the flanges I05. Thus thecircular tracks 92 are retained in positive engagement with thesupporting wheels 95. 96 and 91 during rotation of the feed drum. Thefeed drum II can be removed for replacement or repair by removing thewall bolts I06, which permits disengagement of rollers 96 and 91supported by cross beam I03 from the tracks 92.

sand and crusty particles which have been removed to drop therethroughand fall upon the downwardly inclined bottom wall 25 of the cabi- I ,tomof the elevator.

net and then slide into the hopper 29 at the bot- A sealing gasket 94may be formed of relatively stiff rubber and may be fixedly secured tothe tubular wall of the feed drum II.

The workpieces gravitate from the feed drum II into the blasting chamber4 where they are deposited on the upper trough-shaped flight of acontinuous belt conveyor 12.

particularly in Figs 5, '6, 9-, '10,, 12 and 13,. the

conveyor belt comprises'a pluralityof longitu dinally extending slats H3formed fromheavyv arm portions H3 and a. pairf' of relativelycon---:

As shown more I tracted arm portions H4, 'the-'contracted. arm portionsH4 of one link extending, between the spaced arm portions H3 oftheadjacent link. A link roller H5 is mounted.upon' a pin H5 which extendsthrough the spaced arm portions H3 of one link and theintermediatefcontracted arm portions H4 of the adjacentlinki. The rollerH6 serves'to guide the-conveyor beltirr-its travel to reduce friction;Alate'rally extending. reinforcing rib. I I 3 extendszlatera lly frbmeach: of the arm. portions H3. 4 slat;; s1-il porting-. late H1 ispositioned between each-pair of'rellersand is supported by the -'a,rm;portions-Irl'3,

I I4 and the ribs H3. 'I'l'1e arm-portions' II3:and

m, the rib H3 and the "plate. m supported.

more particularly .in Figs. and 9. The lower portions of the trackmembers I are bolted to a longitudinal frame member I2I whose ends arefixedly secured to the bulkhead walls 33 and 38; The upper ends of thetrack members I2II are secured to spaced frame members I22 whose endsare also secured to the bulkhead walls 33 and 38. The chain'rollers H6carried through the upper flight of the belt roll over thearcuatesurface I23 of the adjacent'trackmember I20, The lower flight of eachchain I3 is also guided in its movement by two or more arcuate-shapedpairedsections I24 and I25. The upper end of each section I24 and' I25is swingably mounted on a shaft I25. The paired shafts I25 are fixedlysecured at their .ends to bulkhead walls 33 and 33. Each series of tracksections I24 and- I25 are connected by an intermediate joining bar I21and a lower Joining'bar I23. The pair of can be drawn in or pushed apartto define the shape of the lower flight of the belt and maintain thebelt under proper tension. The link rollers H6 roll along the outertracklperiphery I32 of the, track sections I24 and I25, thus in- Isu'ring smooth traveling movement of the belt I2.

thereon may be formed as an integral casting or forging. Each slat IIIlrests upon a link plate III of eachchain I3 and may be secured theretoas by screws or rivets H8. It will be noted that the plate II'I providesa slat supporting surface which is inclined with respect to the pathpi'travel of the rollers H5. It will also benoted that the side'edges H9of-each of the'slats H0 are chamfered' or beveled.- As thus constructed,it will be'noted byreferringfto Fig. '9 that the inner'flight of thebelt presents the slats in shingled or overlapped relationship, whilethe outer flight of the belt presents the slats H5 in spacedrelationship. Thus the uptravel side of the inner flight of the belt, asshown at the left hand side of Fig. 9, presents the slats in shingledrelationship, which materially assists the tumbling action withoutdanger that the workpieces or parts thereof will get caught in theslats. Furthermore, relatively small workpieces can be cleaned whensupported .upon the conveyor belt as thus constructed since .even smallworkpieces cannot escape between the slats moving through the uppertrough-shaped flight of the conveyor belt. Since the slats spread apartas the belt travels around its lower or outer flight, it will beappreciated that abrasive, sand, clinkers and other refuse andencrustations removed from the castings and which may be clinging to thebelt, will readily free themselves from the belt and drop into thehopper forming bottom of the cabinet. Each slat lllrmay be provided witha transverse rib I I I which causes positive uptravel of theworkpiecessupported on the inner flight of the belt, Suitable abrasive drainopenings I I9 may also be provided in each of the slats- III). Anarcuate-shaped track member I20 supports the upper flight of each of thechains I3, as shown Eachof the two spaced tumbling belt supporttingshafts I4 and I5 carries sprockets I35 fixed thereto, a pair ofsprockets I35 mounted on the shafts I4 and I5 being provided for eachchain I3. Each sprocket wheel I35 is provided with peripheral lugs I35shaped, spaced and positioned as tov enter the space between the spacedarm portions H3 and the spaced link rollers H5.

The front end of each shaft I4 and I5 is supported by a heavy dutybearing 5I carried by bulkhead wall 33 and the rear end thereof issupported by a heavy duty bearing 52 carried by the bulkhead wall 33, aspreviously described. The belt supporting shaft I4 has an end portionI31 thereof which extends beyond the bearing 5| and carries a drivesprocket I33 thereon. A drive chain I39 extends through an opening I 40in the top wall 32 of the cabinet and is trained around the belt shaftsprocket I35.

The conveyor belt .I2 is driven at any desired speed by drivingmechanism located on the top wall of the cabinet. As shown moreparticularly in Figs. 2 and 3, a tumbling belt driving motor I4! isprovided which is operably connected to reduction gearing I by means ofdrive belt I42. A variable speed device I43 is operably connected togear reducing mechanism I by means of suitable power transmissiondevice. such as interconnecting shaft I44. The belt conveyor drive chainI39 is trained around the sprocket I45 driven by the variable speedmechanism I43, extends through the opening in the top wall 32 of thecabinet, and is trained around sprocket I38 fixed to the end I of thebelt supporting shaft I4. The'variable speed mechanism I43 is of wellknown construction and need not be described in detail. By adjustment ofthe control element I45 of the variable speed mechanism, the conveyorbelt I2 may be driven at any desired speed, so that the speed oftumbling of the workpieces supported on the belt may be regulated as thenature of the workpieces may require.

arranged as to engage the drum lugs I10.

The workpieces w movefrom the conveyor belt I2 into the discharge drum I6. The discharge drum I6 has'a substantially cylindrical wall portionI50 which merges into a flared tubular side wall portion I as'shown moreparticularly in Figs. 5, and 1.1. The flaredzside Wall portion I5I isprovided with a-plurality of holes or openings I52 through which anyabrasive and debris passing into the discharge drum may escape. Thedischarge drum I6 is supported. by a pair of disc forming members I53and I54 fixedly se-, cured to the tubular wall I5I of the drum. Spacedwebportions I55 may be provided to brace and strengthen the discs- I53and I54. Each of the discs I53 and I54 terminates in a laterallyextending flange portion I56 to which isattacheda circular trackmemberI51. Three sets of. paired wheels. I 58', I59 and I60, support the drumin its rotative' movement. The paired wheels I50-are fixed to a shaftI'6I rotatably mounted in spaced bearings .I62 fixed to a bracket I63rigidly secured to the top wall 36 of the cabinet. Paired wheels I 59are fixed to a shaft I64 rotatably mounted in spaced bearings I65carried bylcross beam I66 brackets I 61- removably fixed as by bolts I61to the side walls 2I and. 22 of the cabinet. Similarly, paired wheels Iare fixed to a shaft I64 rotatably mounted in spaced bearings Isupported by resting on the cross beam I66. The paired wheels I50, I59and I60 are each provided with spaced flanges I69 between which thetracks I51 move- It will thus be appreciated that the discharge drum I6is free to rotate about its longitudinal axis. Rotating movement of thedischarge lirum I6 causes the workpieces to tumble therein, shakingloose and removing the abrasive and debris whichmay be clinging theretoThe entry end of the tumbling belt I2 is provided with means forengaging the feed drum II- to rotate the same and the exit end of theconveyor belt I2 is likewiseprovided with engaging the discharge drum I6to rotate the same. By referring more particularly to Figs. 5, 6 and 8,it will be noted that the discharge end of the feed drum II is providedwith a plurality of peripherally spaced lugs I10 projecting therefrom,and that a selectedhumber of the slats III! of the conveyor belt areprovided with a laterally projecting pin 'I1I projecting from the endthereof. The pins I1I carried'by the slats moving around the upperflight of the belt are so It will be appreciated that by thisarrangement the upper flight of the conveyor belt is held to a generallycircular contour which conforms approximately to the outer diameter ofthe feed drum II. The pinsI1I are withdrawn from engagement with thelugs I10 as the slats IIO move over the shaft I4, andlikewise the pinsI1I move into engagement with the lugs I10 when they have moved aroundthe shaft I5. Thus the feed drum I I is positively driven by the drivechain I39 trained around the belt driving sprocket I38.- Each pin I1Imay be welded to a supporting plate I 12 which is secured as by rivetsI13 to the underside of the slat H0.

The discharge drum I6 is likewise rotated about its longitudinal axis bythe tumbling'belt I2. It will be noted by referring more particularly toFigs. 5, 10, 12 and 13 that the adjacent end of certain selected slatsIIO carries a plate I15 on the underside thereof which is securedthereto as by rivets I16. Each plate I15 has insupported by bracingmeans for.

tegrally secured thereto a U-shaped bracket I11 which is reinforced andstiffened by a transverse rib I18. The spaced leg portions I19 of thebracket I11 carry a roller I therebetween which is rotatably mounted ona heavy pin I8I fixed to the leg portions I19 of the bracket. A portionof the roller extends beyond the free edges of the leg portions 119 andthe end of the slat so that it will freely roll along a track I82carried by the bulkhead wall 38, for a purpose presently to bedescribed. The bracket supporting plate I15 also has a vertical wallportion I83 which is substantially flush with the end'of the slat IIOto-which it is secured, A strong and rigid pin I84.is firmly and rigidlysecured, as by welding, to the wall portion I83 of each bracket plateI15. The plate I15, bracket I11, web I18 and vertical wall portion I 83may be formed as a. one-piece casting or forging, and the 'pin I84 theninserted into a hole in the vertical wall portion I83 and welded inposition.

It will be noted by referring to Figs. 5 and 10 that the pins I84carried by the slats engage the outer periphery of the tubular portionI50 of the drum I6 as the tumbling belt moves through its upper flight.To insure positive engagement, the tubular portion I50 may be providedwith lugs I85 which are so spaced and'arranged that each lug is adaptedto be engaged by a pin I84 extending from the end of one of the slats II0. As, hown in Figs. 5, 6 and 10, the ends of alternate slats only needing pins HI and I84, although, if desired, each slat may be providedwith a pin extending from each end thereof. By reason of the fact thatthe pins I84 extend under the tubular portion I50 of the discharge drumI6 during the travel of the conveyor belt through the lower portion ofits upper flight, the discharge end of the upper flight of the conveyorbelt I2 maintains a substantially true arcuate contour which generallyconforms to the arcuate contour of the tubular portion I50 of thedischarge drum I6; It will be'further notedthat the discharge end of theslats III) as they move through the lower portion, of their upper flightare raised slightly above or within the inside diameter of the tubularportion I50 of the discharge drum, so that the workpieces will dropsmoothly from the conveyor belt into the discharge drum I6 withoutobstruction or interference withthe inner receiving edge of thedischarge drum. In this arrangement the drive conveyor belt I 2willoperate to rotate the discharge drum I6 at the same speed as the move.-mentof the upper flight of the conveyor belt.

4 The workpieces within the discharge drum I6 are subjectedto tumblingaction which removes and spills from the surfaces and cavities of theworkpieces any abrasive, sand or other extraneous particles which may beclinging thereto.

It will be noted I2 is raised into a longitudinally tilted or inclinedposition to effect advance movement of the workpieces therethrough, thisconveyor belt would normally have a tendency to swing downwardly or tothe left, as shown in Figs. 2 and 5, with the result that the slatsupporting chains I3 -of the conveyor belt might become dislodged fromSuch movement prevented by the their supporting sprockets I35. of theconveyor belt is definitely .roller track I82 fixed to the bulkhead wall38.

The track I82 may be shaped as shown in Figs. 5 and 10 so as to take theend thrust of the loaded tumbling belt when in tilted position as itmoves through its upper flight and around the shafts be provided withproject-- that when the conveyor belt' ary tubular control cage I4 andI5. It will be noted that the bulkhead wall 38 is so spaced as not tointerfere with the proper tumbling movement of the belt I2 or the properrotation of the discharge drum I8. The rollers I80 carried by thebracket plates I15 are free to roll over the track I62 provided on theinside surface of the bulkhead wall 39 and during their travel willdescribe a path generally similar to the path of travel of the conveyorbelt I2, as shown in Fig. 10. Thus the bulkhead wall 38 takes the endthrust exerted by the tilted and loaded conveyor belt I2 so that thetumbling belt can be operated with a minimum of friction.

A stream of abrasive a of generally fan-shaped contour, as shown in Fig.5, is projected into the trough-shaped cavity formed by the upper flightof the conveyor belt I2, by means of a suitable abrasive projectorpreferably comprising a centrifugal abrasive throwing wheel I0. Suchabrasive throwing wheels are well known in the art, but for purposes ofillustration there is shown in Figs. 5 and 9 a centrifugal abrasivethrowing wheel of well-known construction, comprising a pair of spacedciicular discs I90 and I'9I held in spaced relationship by suitablespacing studs I92. Radially arranged channel-shaped abrasive throwingblades I93 are positioned between and supported by the side wall discsI90 and I9I but may be removed outwardly through the periphery of thewheel when worn. The blades are held in position by suitable lockingscrews I94 which extend through one or both side wall discs of the wheeland engage adjacent side edges of the blades. The blades extend inwardlyshort of the axis of rotation of the wheel to provide a central spaceinto which extends a normally station- I95 having a discharge port I96in the peripheral wall thereof through which the abrasive escapes andmoves into the path of rotation of the blades. A central impeller I91fixed to the end of the wheel shaft I98 as by a bolt I99, operates toproject the abrasive through the discharge port I96 in the control cageI95. The impeller is provided with a plurality of equally spaced vanes200 equal in number to the blades I93, which vanes pick up the abrasivefed into the central portion of the impeller and projects this abrasiveout through the discharge port I96 in the control cage. The wheel issecured to its drive shaft I99 by a hub 202. The wheel shaft I99 isrotatably supported in a pair of spaced dustproof bearings 203 supportedon the top wall 35 of the cabinet. A driving motor 204 of suitablehorsepower is operably connected to a drive sheave 205 fixed to the endof the wheel shaft I98 by means of a V-belt drive 206 which is alsotrained around the sheave 201 attached to the motor shaft. An abrasivethrowing wheel of the type above described may be made any size so as tothrow from 200 to 2000 lbs. of abrasive per minute at blasting velocity.The wheel throws a generally fan-shaped stream defining a longitudinalimpingement pattern and the direction of night of the thrown abrasivemay be accurately controlled by proper adjustment of the clockdialposition of the discharge outlet I96 in the' control cage I95.

It will be noted by referring more particularly to Fig. 9 that the wheelshaft I98 is inclined to the horizontal so that the plane of rotation ofthe wheel I0 is inclined to the vertical in such a position as to directthe fan-shaped stream of abrasive a at an angle to the vertical andslightly to one side of the vertical center line drawn through themidsection of the upper flight of the conveyor belt. shewn in Fig. 9,the upper flight of the conveyor belt travels to the left,

thus causing the workpieces to travel upwardly along the left-handupwardly moving section of the upper flight until the angle ,of reposeof the workpieces is overcome, whence they topple over into the bottomof the trough. By inclining the abrasive throwing wheel III at an angleto the vertical, as shown in Fig. 9, the abrasive stream a will impingethe main body of castings supported within the upper flight of theconveyor belt, so that the heaviest moving body of workpieces aredirectly within-the abrasive blast. The workpieces can thus be cleanedmore thoroughly and with greater speed.

It will also be noted that the conveyor belt supporting shaft I4 isarranged at a slightly higher elevation than the belt supporting shaftI5, so that the tumbling belt bellies inwardly at this point, thusobtaining a positive and complete turning of the ,workpieces undergoingtreatment. It will be further noted that those conveyor slats III) whichare moving across the bottom and up the left-hand side of the conveyorbelt arrange themselves in shingled overlapped relationship,

thus removing the possibility of any of the workpieces clinging to theslats or dropping through the slats. When the slats travel through thelower flight of the conveyor belt, they are substantially spaced apartso as to readily release abrasive and foreign particles which mightotherwise cling to the slats or to the links which support the slats.

Abrasive is fed into the central portion of the control cage I through asupply spout 2I0. The supply spout 2I0 extends through an aperture 2 ina narcuate-shaped fan housing 2I2. The lower portion of the wheelextends through an opening 2I3 in the top wall 35 of the cabinet. Thefan housing -comprises a four-sided boxshaped wall 2Il having outwardlyflared foot portions 2I5 which are bolted to the top wall 35 of theblasting chamber. The top edge of the box structure 2 of the wheelhousing extends to substantially midsection of the shaft I99. Anarcuate-shaped groove 2I6 is provided in one wall of the box structurethrough which the shaft I98 extends. The opposite side wall of the boxstructure 2I4 is also provided with a suitable arcuate cut-out whichforms a part of a suitable hole 2 through which the feed spout 2I0extends. The upper portion of the wheel housing comprises anarcuate-shaped top wall 2I8 joined to side walls 2 I 9, the side wallsresting upon the top edge of the box structure 2. One'lower edge of thearcuate top wall 2I9 may be hinged as at 220 so that the top portion ofthe housing may be swung open to give access to the wheel. A suitablelatch 22I may be provided to retain the cover portion of the housing inclosed position. A pair of spaced guard plates are fixed to the top wall35 of the cabinet and extend below the wheel receiving opening 2 I 3.The guard plates 223 protect the rapidly rotating wheel I0 from possiblecontact with a moving or tumbling workpiece.

It willbe noted by referring more particularly to Figs. 2, 3 and 4 thatthe feed spout 2I0 is connected to an abrasive receiving hopper 225which has relatively narrow end walls 226 and flared side walls 221presenting a hopper opening in the top which is of considerable length.

Abrasive is supplied to the hopper 225 through a supply spout 228 at thelower end of a funnel 229 of an abrasive supply bin 239. A pivotallymounted valve 23I may be mounted on the end I of the supply'spout 2Z8;tocohtlolithe fiowjrofk abrasive into the'hopper 225; It willb'e'app'recition of the cabinet, the elongated mouthof the. v

hopper 225 is always in position to catch the abrasive flowing from thestationary feed spout 228. e

The abrasive and foreign matter dropping into the boot hopper 29 flowsinto the lower end of the elevator tower 30-, where it is picked :up'bythe elevator buckets 236 carried by the continuous elevator chain 231.The lower end" of the elevator chain 231 is trained around a rotatablesprocket 238 positioned within the lower end of the elevator tower 38,and the upper end of the chain is trained around a sprocket 239rotatively mounted in the upper end of the elevator tower 30. A drivingmotor 235 supported upon a suitable pedestal bracket 240 fixed to theupper end of the elevator tower, is connected through a speed reducer 2to a drive sheave 242 fixed to the protruding shaft of the speedreducer. A

drive belt 243' is trained around the sheave 242 and the sheave 243fixed to the end of the shaft 244 which supports thesprocket 239.

v The abrasive is discharged from the elevator buckets 236 as they moveover'the sprocket 239 into a conveyor tube 245 which projects into theabrasive bin 230. A feed screw 246 is rotatably mounted in the tube 245,this screw being rotatably supported by bearings 241 and 248. One end;

of the feed screw 246 is provided with a shaft portion 248' whichextends through the bearing 241 and carries a'sprocket 249 fixedthereto. A

drive chain 258 is trained around the sprocket 249 and a sprocket 25|fixed to the end of the shaft 244 which carries the bucket Supportingsprocket 239.

As shown more particularly in Fig. 3, a circular stationary screen' 255is mounted within the abrasive bin 230 into which the abrasive andforeign particles drop from the end of the conduit 245.

enlarged screw flights 256 which rotate within the normallystationary-circular screen 255. The

flights 256 of the screw agitate the abrasive and foreign particleswithin the circular screen 255, causing the abrasive particles to dropthrough the screen and into the bin 23!). The foreign particles, andparticularly clinkers and such'foreign matter that cannot pass throughthe screen,

are conveyed out through the end of the screen and dropped into adischarge pipe 251 from which they roll in a downward direction anddischarge from the lower end 258 thereof.

For convenience in repairing or making ad- Justments to the mechanism atthe top of the elevator tower, a platform 260 may be provided for theconvenience of the operator, as shown more particularly in Figs. 1', 2,3 and 4. The

platform 26!] may comprise a metal plate which is supported by a pair ofpost members 26l located adjacent the side wall 22 of the cabinet, and apost member 262 spaced from but generally in alignment with the elevatortower 30. A skeleton frame supported by the posts 26l and 262 andelevator tower 30 provides a framework upon which the platform 260rests. This frame structure may comprise a horizontal beam member 263secured to upright posts 26! horizontal beam member 264 secured to oneof the posts 26l and The feed screw 246 is provided with to the platform280 able standard. The concave belt nected to the sheave 218 attached toconveyors may concave conveyor belt 29l the esms2,=a eaiimemb 126,6-secured, to the 'o'th'er'post "261 and to theside 'of the elevatortower-.30, a cross beam 261 secured to beam 263 ,andto the other side'ofthe elevator tower 30.

inspect or repair-the mechanism at the top oi.

the elevator tower. A guard railing 269 secured may'also be provided.

The workpieces may be supplied to the hopper 2- by means of acontinuous-feed'belt'fll which may extend to any convenient location inthe plant where the workpieces are to be found. The lower end of thebelt may be supported on a concave-shaped roller 212 fixed to a shaft213' which is rotatably mounted in bearings 214 of a suit- 21!.is'driven by a motor 215 operably connected to speed reducing' gearing216 by drive belt 211, the reduction gearing 216 being in turn operablycon the end of theroller shaft 213 by drive belt 219. The dischargeend'of the belt is trained arms 28l secured to the hopper 2. A take-upably, mounted inthe arms 283 of the supporting bracket 28h It will beappreciated that various difierentfkinds'of continuous workpiece feedingbe provided to supply workpieces to the hopper 2 in a continuous stream.It is therefore understood thatthe conveyor belt'ar- 'rangement isheredescribed merely to show one type of conveyor which may be used forthis purpose. r

The workpieces discharged from the rotating discharge drum l8 may bereceived in a suitable stationary inclined discharge chute 285, as shownin'Figs. 2 and 4. This discharge chute may be provided with holes orperforations 286 in the bottom thereof through which abrasive or foreignmaterial may sift into a receiving hopper 281 which discharges into aboot hopper 288 at the bottom of the elevator tower 30. The boot hopper286 communicates with the interior of the elevator tower 30 where theabrasive and foreign materials may be readily picked up by the elevatorbuckets 236. The sides of the chute 285 carry a horizontally extendingapron 289 from which hang a series of flexible rubber curtains 290 whichpermit the workpieces to readily escape but prevents the escape ofabrasive, dust and debris from the cabinet.

The cleaned workpieces discharged from the chute 285 maybe arranged todrop on a suitable which extends under 285. The belt 29! is supportingroller 292 suitable standard 293 the lower end of the chute trainedaround a concave rotatably supported by a resting upon the mill floor2!" may extend to any convenient location in the plant where furtheroperations may be performed upon the cleaned and treated workpieces.

There is shown in Fig. 14 a continuous blast cleaning mill which issubstantially identical with the mill above described, except that thetumbling belt I2 is somewhat longer so as to receive .the blast from twoor more abrasive throwing wheels l0. Where the tumbling belt I2 is thusappreciably lengthened, it may be desirable to support the same uponthree or more belt chains l3. It is understood that an abrasive supplyarounda con-i cave roller 280 supported upon spaced bracket f. Theconveyor belt.

into the feed drum ll.

hopper 225 is provided for each wheel, which are both fed from acommon-abrasive supply bin 23!! by individual supply spouts 228. ciatedthat the mill may be of any desired size and capacity to properly handlethe volume of production desired. .The mill shown in Fig. 14 ispartially contained in a floor pit I, access to the bottom of the pitbeing had by a suitable stairway 259.

Operation In operating this blast cleaning apparatus, the abrasivecycling system is first put into operation to supply the abrasive bin230 with the proper quantity of selected abrasive. The elevator motor235 which drives the elevator buckets 236 supported on chains 231, isthrown into operation and abrasive is dumped into the receivers 29 atthe boot of the elevator. The elevator buckets 23G empty the abrasiveinto the horizontal abrasive conduit 245, whence it is carried by feedscrew 246 into the stationary screen 255 and then drops into the bin.

The operator throws the tumbling belt l2 into operation by turning theswitch which supplies current to its driving motor 1. The feed drum IIand the discharge drum l5 are thus caused to rotate. The conveyor belt21! is advanced by throwing the belt driving motor 215 into operation.'The workpieces placed thereon empty into the feed hopper 2, whence theyroll The workpieces tumble, advance or spiral through the feed drum IIand onto the upper flight of the tumbling belt l2. When there aresufflcient workpieces supported on the upper flight of the tumbling beltl2 to protect the slats thereof, the abrasive throwing wheel or wheelsIII are thrown into operation by turning on the current which issupplied to the wheel driving motor or motors 204. Abrasive is thensupplied to the wheel or wheels in the proper quantity by manipulatingthe control valve 23| on the supply spout 228 of the abrasive bin 230.Dust and other air-suspended materials may be drawn out of the cabinetby a suitable suction fan connected to the dust discharge ports I33, I41and I2 in the. top wall of the cabinet, as shown in Fig.1.

The proper inclination of the tumblin belt l2 and associated feed drum Hand dischar e drum l6 as well as the speed at which these parts shouldbe driven, is determined by several fac: tors, including the physicalcharacteristics shape and hardness of the workpieces, the amount andcharacter of surface debris. scale, encrustations and projections to beremoved therefrom, the nature and sharpness oi the abrasive employed,the longitudinal length of the tumbling belt l2, and the number andcapacity of the abrasive throwing wheels l0 employed. The type and kindof abrasive to be employed in cleaning and removing theencrustationsappearing on a particular class of workpieces is generallyknown to those skilled in the art, either steel shot or steel grit of aselected size being generally employed. With a given number of abrasivethrowing wheels of known capacity and with a tumbling belt i2 of knownlength, the proper inclination to be given the belt l2 and the properspeed at which the belt should be driven can easily be determinedexperimentally until the operator becomes experienced enough to knowwhat these factors should be. For example, some types of workpieces mayrequire residence on the tumbling belt a matter of only three minutes tobecome It is apprebut this time interval is again largely affected bythe number of wheels, the capacity of the wheels and the cutting natureof the abrasive employed.

When the selected workpieces begin to discharge into the discharge chute285, they are carefully examined to determine whether they have beencleaned and treated the amount desired. If they indicate overcleaning,the tumblingbelt may be raised to a greater inclination bymanipulatingthe hydraulic jack through the control handle 83. The speed of travel ofthe tumbling belt may also be increased by manipulating the controlhandle I on the speed control mechanism 3. If the workpieces areundercleaned, the speed of travel of the tumbling belt I? may bedecreased and the angle of inclination of the tumbling belt may also bedecreased to suit conditions, Ordinarily the angle of inclination of thefeed drum, tumbling belt and discharge drum, to take care of a selectedtype of workpieces, will vary from substantially 0 to 20. The operatorwill quickly learn from experience what these operating factors shouldbe for the particular type of workpieces to be cleaned and treated.

In viewof the great flexibility of this blast cleaning and treatingunit, numerous different kinds and types of castings, forgings,stampings and other metal workpieces can be thoroughly and effectivelycleaned and treated at high production speeds, which have heretoforerequired special types of workhandling devices to prop erly turn the[workpieces so as to present their various surfaces, projections andcavities to the abrasive blast. This improved apparatus thus has a wideand general application to the cleaning of various types and kinds ofworkpieces.

While certain novel features of the invention have been disclosed andare pointed out in the annexed claims, it will be understood thatvarious omissions, substitutions and changes may be made by thoseskilled. in the art without departing from the spirit of the invention.

What is claimed is:

1. In blast cleaning apparatus, a tumbling belt, means for supportingsaid belt to present a generally concave workpiece supporting surface,means for driving said belt to effect tumbling of the workpiecessupported therein along a concave sector thereof, said belt comprising aplurality of longitudinally extending slats which form the workpiecesupporting surface, flexible elements connecting said slots in generallyparallel relationship, and means for securing said slats to saidflexible elements in position relatively inclined with respect to thepath of travel of said flexible elements whereby said slatsautomatically arrange themselves in generally overlapped shingledrelationship during their path of travel along the concave workpiecesupporting sector thereof.

2. In blast cleaning apparatus, a continuous tumbling belt, means forsuspending said belt that the upper flight thereof deflnes a generallyconcave workpiece supporting surface, and means for driving said belt toeffect tumbling of the workpieces within the upper flight thereof, saidbelt comprising a plurality of spaced chains each comprising a series ofhingedly connected links and longitudinally extending slats connected toa link of each chain, said links each having a supporting portion shapedto support said slats in generally shingled overlapped relationshipduring their travel through the upper flight and in gentravel throughthe lower flight. I

3. In blast cleaning apparatus, a continuous erally spaced relationshipduring their path of flexible tumbling belt, a pair of spaced supportsextending longitudinally of the belt and supporting the same to definean inner concave workpiece supporting. flight and an outerflight, andmeans trackways 'for guidingsaid belt during its movement through theinner. flight thereof, spaced outer trackways'for guiding said beltduring its movement through the outer flight thereof, and

' means for adjusting said'outer trackways to tension said belt.

4. In blast cleaning apparatus, a'continuous flexible tum-bling belt, apair of spaced supports extending longitudinally of the belt and supporting the same to define an inner concave workpiece supporting flightandan outer flight, means formaintaining the shape of the inner flightto a predetermined contour, including a pair of swingably mountedexpansion sections normally adapted to bear against the inside surfaceof the lower flight of the belt, and adjusting means operably connectedto'said paired sections for maintaining a predetermined tension on saidbelt, i

' 5. In blast cleaning apparatus, a flexible tumbling belt, a pair ofspaced supports extending longitudinally of the belt for supporting thesame to define an inner concave workpiece supporting flight, means forrotating one of said supports to drive said belt, a tubular feed drumhaving its 1ongitudinal axis generally in line with the longitudinalaxis of the concave supporting flight of said belt, and interconnectingprojections associated with the adjacent ends of said belt and saiddrumfor maintaining the contour of the upper flight to a predeterminedconcave shape, said interccn- 7 necting projections further serving torotate said feed drum with the movement of the concave workpiecesupporting flight of said belt.

' 6. In blast cleaning apparatus, a flexible tumbling belt, a pair ofspaced supports extending longitudinally of the belt for supporting thesame to define an inner; concave workpiece supporting flight, a tubulardischarge drum having its longitudinal axis generally in line with thelongitudinal axis of the concave supporting flight of said belt, andinterconnecting projections associated with the adjacent'ends of saidbelt and said drum for maintaining the contour of the upper flight to apredetermined concave shape, and means for rotating one of said supportsto drive said belt and rotate said drum.

7. In blast cleaning apparatus, a flexible tumbling belt, a pair ofspaced supports extending longitudinally of the belt and supporting thesame to define an inner concave workpiece supporting flight, means fortilting said supports and said belt in a direction generallylongitudinally thereof, a bulkhead wall at the normally lower end ofsaid belt, and thrust rollers positioned between the lower end of saidbelt and said bulkhead for transferring the thrust from the lower end ofthe belt to said bulkhead wall.

8. In blast cleaning apparatus, a flexible tumblin belt, a pair ofspaced supports extending longitudinally of the belt and supporting thesame to deflne an inner workpiece supporting flight, and means fortilting said support and said belt in a direction generallylongitudinally thereof, a bulkextending longitudinally of the belt andsupporting the same to define an inner'workpiece supporting flight andan outer flight, means for maintaining said inner flight to apredetermined concave contour, means for rotating one of said supportsto cause said belt to travel around said sup- I ports and generallytransversely thereof to effect tumbling movement of the workpiecessupported on the inner concave flight thereof, an abrasive throwingwheel operative to project a fan-shaped stream of abrasive into theconcave workpiece supporting flight of said belt, a high speed shaft forrotating said wheel extending in a direction generally transversely tosaid supports whereby the longitudinal axis of said fan-shaped streamextends in the general direction of the longitudinal axis of saidconcave workpiece supporting flight, said shaft being inclined so as tosupport said wheel with its plane of rotation inclined to the verticalso that the stream of abrasive projected therefrom will be directedtoward the uptravel side of the concave workpiece supporting flight ofthe belt, and 'a pair of spaced bailies between which the lower portionof said wheel is positioned, the said bafiles extending into saidworkpiece supporting flight operative to prevent the workpieces fromcontacting said wheel.

10. In blast cleaning apparatus, a cabinet, a continuous flexibletumbling belt, a pair of spaced supports, extending longitudinally ofthe belt for supporting the same to define an inner concave workpiecesupporting flight and an outer flight, means for rotating one of saidsupports to drive said belt, a tubular feed drum having open endspositioned within said cabinet operative to supply workpieces to theinner workpiece supporting workpieces tumbled therein may escape.

11. In blast cleaning apparatus, a cabinet, 8. continuous flexibletumbling belt, a pair of spaced supports extending longitudinally of thebelt for supporting the same to deflne an inner concave workpiecesupporting flight and an outer flight, means for rotating one of saidsupports to drive said belt, a discharge drum positiongd'sto receiveworkpieces from said belt having a gengrally cylindrical portion merginginto a generally outwardly flared truncated conical portion rotatablymounted in said cabinet, a pair of spaced circular tracks fixed'to theouter periphery of said drum,'a plurality of spaced rollers engagingsaid tracks for rotatably supporting said drum, roller supports withinsaid'cabinet, interconnecting means associated with the adjacent ends ofsaid belt and said

